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Creating and Sending Notifications

Installation

Current web applications use many different channels to send messages to the users (e.g. SMS, Slack messages, emails, push notifications, etc.). The Notifier component in Symfony is an abstraction on top of all these channels. It provides a dynamic way to manage how the messages are sent. Get the Notifier installed using:

$ composer require symfony/notifier

Channels: Chatters, Texters, Email, Browser and Push

The notifier component can send notifications to different channels. Each channel can integrate with different providers (e.g. Slack or Twilio SMS) by using transports.

The notifier component supports the following channels:

Tip

Use :doc:`secrets </configuration/secrets>` to securely store your API tokens.

SMS Channel

Caution!

If any of the DSN values contains any character considered special in a URI (such as +, @, $, #, /, :, *, !), you must encode them. See RFC 3986 for the full list of reserved characters or use the :phpfunction:`urlencode` function to encode them.

The SMS channel uses :class:`Symfony\\Component\\Notifier\\Texter` classes to send SMS messages to mobile phones. This feature requires subscribing to a third-party service that sends SMS messages. Symfony provides integration with a couple popular SMS services:

Service Package DSN Webhook support
46elks symfony/forty-six-elks-notifier forty-six-elks://API_USERNAME:API_PASSWORD@default?from=FROM  
AllMySms symfony/all-my-sms-notifier allmysms://LOGIN:APIKEY@default?from=FROM  
AmazonSns symfony/amazon-sns-notifier sns://ACCESS_KEY:SECRET_KEY@default?region=REGION  
Bandwidth symfony/bandwidth-notifier bandwidth://USERNAME:PASSWORD@default?from=FROM&account_id=ACCOUNT_ID&application_id=APPLICATION_ID&priority=PRIORITY  
Brevo symfony/brevo-notifier brevo://API_KEY@default?sender=SENDER  
Clickatell symfony/clickatell-notifier clickatell://ACCESS_TOKEN@default?from=FROM  
ContactEveryone symfony/contact-everyone-notifier contact-everyone://TOKEN@default?&diffusionname=DIFFUSION_NAME&category=CATEGORY  
Esendex symfony/esendex-notifier esendex://USER_NAME:PASSWORD@default?accountreference=ACCOUNT_REFERENCE&from=FROM  
FakeSms symfony/fake-sms-notifier fakesms+email://MAILER_SERVICE_ID?to=TO&from=FROM or fakesms+logger://default  
FreeMobile symfony/free-mobile-notifier freemobile://LOGIN:API_KEY@default?phone=PHONE  
GatewayApi symfony/gateway-api-notifier gatewayapi://TOKEN@default?from=FROM  
GoIP symfony/goip-notifier goip://USERNAME:PASSWORD@HOST:80?sim_slot=SIM_SLOT  
Infobip symfony/infobip-notifier infobip://AUTH_TOKEN@HOST?from=FROM  
Iqsms symfony/iqsms-notifier iqsms://LOGIN:PASSWORD@default?from=FROM  
KazInfoTeh symfony/kaz-info-teh-notifier kaz-info-teh://USERNAME:PASSWORD@default?sender=FROM  
LightSms symfony/light-sms-notifier lightsms://LOGIN:TOKEN@default?from=PHONE  
Mailjet symfony/mailjet-notifier mailjet://TOKEN@default?from=FROM  
MessageBird symfony/message-bird-notifier messagebird://TOKEN@default?from=FROM  
MessageMedia symfony/message-media-notifier messagemedia://API_KEY:API_SECRET@default?from=FROM  
Mobyt symfony/mobyt-notifier mobyt://USER_KEY:ACCESS_TOKEN@default?from=FROM  
Nexmo symfony/nexmo-notifier Abandoned in favor of Vonage (symfony/vonage-notifier).  
Octopush symfony/octopush-notifier octopush://USERLOGIN:APIKEY@default?from=FROM&type=TYPE  
OrangeSms symfony/orange-sms-notifier orange-sms://CLIENT_ID:CLIENT_SECRET@default?from=FROM&sender_name=SENDER_NAME  
OvhCloud symfony/ovh-cloud-notifier ovhcloud://APPLICATION_KEY:APPLICATION_SECRET@default?consumer_key=CONSUMER_KEY&service_name=SERVICE_NAME  
Plivo symfony/plivo-notifier plivo://AUTH_ID:AUTH_TOKEN@default?from=FROM  
Redlink symfony/redlink-notifier redlink://API_KEY:APP_KEY@default?from=SENDER_NAME&version=API_VERSION  
RingCentral symfony/ring-central-notifier ringcentral://API_TOKEN@default?from=FROM  
SMSFactor symfony/sms-factor-notifier sms-factor://TOKEN@default?sender=SENDER&push_type=PUSH_TYPE  
Sendberry symfony/sendberry-notifier sendberry://USERNAME:PASSWORD@default?auth_key=AUTH_KEY&from=FROM  
Seven.io symfony/sevenio-notifier sevenio://API_KEY@default?from=FROM  
SimpleTextin symfony/simple-textin-notifier simpletextin://API_KEY@default?from=FROM  
Sinch symfony/sinch-notifier sinch://ACCOUNT_ID:AUTH_TOKEN@default?from=FROM  
Sms77 symfony/sms77-notifier sms77://API_KEY@default?from=FROM  
SmsBiuras symfony/sms-biuras-notifier smsbiuras://UID:API_KEY@default?from=FROM&test_mode=0  
SmsSluzba symfony/sms-sluzba-notifier sms-sluzba://USERNAME:PASSWORD@default  
Smsapi symfony/smsapi-notifier smsapi://TOKEN@default?from=FROM  
Smsbox symfony/smsbox-notifier smsbox://APIKEY@default?mode=MODE&strategy=STRATEGY&sender=SENDER  
Smsc symfony/smsc-notifier smsc://LOGIN:PASSWORD@default?from=FROM  
SpotHit symfony/spot-hit-notifier spothit://TOKEN@default?from=FROM  
Telnyx symfony/telnyx-notifier telnyx://API_KEY@default?from=FROM&messaging_profile_id=MESSAGING_PROFILE_ID  
TurboSms symfony/turbo-sms-notifier turbosms://AUTH_TOKEN@default?from=FROM  
Twilio symfony/twilio-notifier twilio://SID:TOKEN@default?from=FROM yes
Unifonic symfony/unifonic-notifier unifonic://APP_SID@default?from=FROM  
Vonage symfony/vonage-notifier vonage://KEY:SECRET@default?from=FROM yes
Yunpian symfony/yunpian-notifier yunpian://APIKEY@default  
iSendPro symfony/isendpro-notifier isendpro://ACCOUNT_KEY_ID@default?from=FROM&no_stop=NO_STOP&sandbox=SANDBOX  

Tip

Some third party transports, when using the API, support status callbacks via webhooks. See the :doc:`Webhook documentation </webhook>` for more details.

.. versionadded:: 7.1

    The `SmsSluzba`_ integration was introduced in Symfony 7.1.

.. deprecated:: 7.1

    The `Sms77`_ integration is deprecated since
    Symfony 7.1, use the `Seven.io`_ integration instead.

To enable a texter, add the correct DSN in your .env file and configure the texter_transports:

# .env
TWILIO_DSN=twilio://SID:TOKEN@default?from=FROM
.. configuration-block::

    .. code-block:: yaml

        # config/packages/notifier.yaml
        framework:
            notifier:
                texter_transports:
                    twilio: '%env(TWILIO_DSN)%'

    .. code-block:: xml

        <!-- config/packages/notifier.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:notifier>
                    <framework:texter-transport name="twilio">
                        %env(TWILIO_DSN)%
                    </framework:texter-transport>
                </framework:notifier>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/notifier.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $framework->notifier()
                ->texterTransport('twilio', env('TWILIO_DSN'))
            ;
        };

The :class:`Symfony\\Component\\Notifier\\TexterInterface` class allows you to send SMS messages:

// src/Controller/SecurityController.php
namespace App\Controller;

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Notifier\Message\SmsMessage;
use Symfony\Component\Notifier\TexterInterface;
use Symfony\Component\Routing\Annotation\Route;

class SecurityController
{
    #[Route('/login/success')]
    public function loginSuccess(TexterInterface $texter): Response
    {
        $options = (new ProviderOptions())
            ->setPriority('high')
        ;

        $sms = new SmsMessage(
            // the phone number to send the SMS message to
            '+1411111111',
            // the message
            'A new login was detected!',
            // optionally, you can override default "from" defined in transports
            '+1422222222',
            // you can also add options object implementing MessageOptionsInterface
            $options
        );

        $sentMessage = $texter->send($sms);

        // ...
    }
}

The send() method returns a variable of type :class:`Symfony\\Component\\Notifier\\Message\\SentMessage` which provides information such as the message ID and the original message contents.

Chat Channel

Caution!

If any of the DSN values contains any character considered special in a URI (such as +, @, $, #, /, :, *, !), you must encode them. See RFC 3986 for the full list of reserved characters or use the :phpfunction:`urlencode` function to encode them.

The chat channel is used to send chat messages to users by using :class:`Symfony\\Component\\Notifier\\Chatter` classes. Symfony provides integration with these chat services:

.. versionadded:: 7.1

    The ``Bluesky``, ``Unifonic`` and ``Smsbox`` integrations
    were introduced in Symfony 7.1.

Caution!

By default, if you have the :doc:`Messenger component </messenger>` installed, the notifications will be sent through the MessageBus. If you don't have a message consumer running, messages will never be sent.

To change this behavior, add the following configuration to send messages directly via the transport:

# config/packages/notifier.yaml
framework:
    notifier:
        message_bus: false

Chatters are configured using the chatter_transports setting:

# .env
SLACK_DSN=slack://TOKEN@default?channel=CHANNEL
.. configuration-block::

    .. code-block:: yaml

        # config/packages/notifier.yaml
        framework:
            notifier:
                chatter_transports:
                    slack: '%env(SLACK_DSN)%'

    .. code-block:: xml

        <!-- config/packages/notifier.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:notifier>
                    <framework:chatter-transport name="slack">
                        %env(SLACK_DSN)%
                    </framework:chatter-transport>
                </framework:notifier>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/notifier.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $framework->notifier()
                ->chatterTransport('slack', env('SLACK_DSN'))
            ;
        };

The :class:`Symfony\\Component\\Notifier\\ChatterInterface` class allows you to send messages to chat services:

// src/Controller/CheckoutController.php
namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Notifier\ChatterInterface;
use Symfony\Component\Notifier\Message\ChatMessage;
use Symfony\Component\Routing\Annotation\Route;

class CheckoutController extends AbstractController
{
    /**
     * @Route("/checkout/thankyou")
     */
    public function thankyou(ChatterInterface $chatter): Response
    {
        $message = (new ChatMessage('You got a new invoice for 15 EUR.'))
            // if not set explicitly, the message is sent to the
            // default transport (the first one configured)
            ->transport('slack');

        $sentMessage = $chatter->send($message);

        // ...
    }
}

The send() method returns a variable of type :class:`Symfony\\Component\\Notifier\\Message\\SentMessage` which provides information such as the message ID and the original message contents.

Email Channel

The email channel uses the :doc:`Symfony Mailer </mailer>` to send notifications using the special :class:`Symfony\\Bridge\\Twig\\Mime\\NotificationEmail`. It is required to install the Twig bridge along with the Inky and CSS Inliner Twig extensions:

$ composer require symfony/twig-pack twig/cssinliner-extra twig/inky-extra

After this, :ref:`configure the mailer <mailer-transport-setup>`. You can also set the default "from" email address that should be used to send the notification emails:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/mailer.yaml
        framework:
            mailer:
                dsn: '%env(MAILER_DSN)%'
                envelope:
                    sender: '[email protected]'

    .. code-block:: xml

        <!-- config/packages/mailer.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:mailer
                    dsn="%env(MAILER_DSN)%"
                >
                    <framework:envelope
                        sender="[email protected]"
                    />
                </framework:mailer>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/mailer.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $framework->mailer()
                ->dsn(env('MAILER_DSN'))
                ->envelope()
                    ->sender('[email protected]')
            ;
        };

Push Channel

Caution!

If any of the DSN values contains any character considered special in a URI (such as +, @, $, #, /, :, *, !), you must encode them. See RFC 3986 for the full list of reserved characters or use the :phpfunction:`urlencode` function to encode them.

The push channel is used to send notifications to users by using :class:`Symfony\\Component\\Notifier\\Texter` classes. Symfony provides integration with these push services:

Service Package DSN
Engagespot symfony/engagespot-notifier engagespot://API_KEY@default?campaign_name=CAMPAIGN_NAME
Expo symfony/expo-notifier expo://Token@default
Novu symfony/novu-notifier novu://API_KEY@default
Ntfy symfony/ntfy-notifier ntfy://default/TOPIC
OneSignal symfony/one-signal-notifier onesignal://APP_ID:API_KEY@default?defaultRecipientId=DEFAULT_RECIPIENT_ID
PagerDuty symfony/pager-duty-notifier pagerduty://TOKEN@SUBDOMAIN
Pushover symfony/pushover-notifier pushover://USER_KEY:APP_TOKEN@default

To enable a texter, add the correct DSN in your .env file and configure the texter_transports:

# .env
EXPO_DSN=expo://TOKEN@default
.. configuration-block::

    .. code-block:: yaml

        # config/packages/notifier.yaml
        framework:
            notifier:
                texter_transports:
                    expo: '%env(EXPO_DSN)%'

    .. code-block:: xml

        <!-- config/packages/notifier.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:notifier>
                    <framework:texter-transport name="expo">
                        %env(EXPO_DSN)%
                    </framework:texter-transport>
                </framework:notifier>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/notifier.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $framework->notifier()
                ->texterTransport('expo', env('EXPO_DSN'))
            ;
        };

Configure to use Failover or Round-Robin Transports

Besides configuring one or more separate transports, you can also use the special || and && characters to implement a failover or round-robin transport:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/notifier.yaml
        framework:
            notifier:
                chatter_transports:
                    # Send notifications to Slack and use Telegram if
                    # Slack errored
                    main: '%env(SLACK_DSN)% || %env(TELEGRAM_DSN)%'

                    # Send notifications to the next scheduled transport calculated by round robin
                    roundrobin: '%env(SLACK_DSN)% && %env(TELEGRAM_DSN)%'

    .. code-block:: xml

        <!-- config/packages/notifier.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:notifier>
                    <!-- Send notifications to Slack and use Telegram if
                         Slack errored -->
                    <framework:chatter-transport name="slack">
                        %env(SLACK_DSN)% || %env(TELEGRAM_DSN)%
                    </framework:chatter-transport>

                    <!-- Send notifications to the next scheduled transport
                         calculated by round robin -->
                    <framework:chatter-transport name="slack"><![CDATA[
                        %env(SLACK_DSN)% && %env(TELEGRAM_DSN)%
                    ]]></framework:chatter-transport>
                </framework:notifier>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/notifier.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            $framework->notifier()
                // Send notifications to Slack and use Telegram if
                // Slack errored
                ->chatterTransport('main', env('SLACK_DSN').' || '.env('TELEGRAM_DSN'))

                // Send notifications to the next scheduled transport calculated by round robin
                ->chatterTransport('roundrobin', env('SLACK_DSN').' && '.env('TELEGRAM_DSN'))
            ;
        };

Creating & Sending Notifications

To send a notification, autowire the :class:`Symfony\\Component\\Notifier\\NotifierInterface` (service ID notifier). This class has a send() method that allows you to send a :class:`Symfony\\Component\\Notifier\\Notification\\Notification` to a :class:`Symfony\\Component\\Notifier\\Recipient\\Recipient`:

// src/Controller/InvoiceController.php
namespace App\Controller;

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\Notifier\Notification\Notification;
use Symfony\Component\Notifier\NotifierInterface;
use Symfony\Component\Notifier\Recipient\Recipient;

class InvoiceController extends AbstractController
{
    #[Route('/invoice/create')]
    public function create(NotifierInterface $notifier): Response
    {
        // ...

        // Create a Notification that has to be sent
        // using the "email" channel
        $notification = (new Notification('New Invoice', ['email']))
            ->content('You got a new invoice for 15 EUR.');

        // The receiver of the Notification
        $recipient = new Recipient(
            $user->getEmail(),
            $user->getPhonenumber()
        );

        // Send the notification to the recipient
        $notifier->send($notification, $recipient);

        // ...
    }
}

The Notification is created by using two arguments: the subject and channels. The channels specify which channel (or transport) should be used to send the notification. For instance, ['email', 'sms'] will send both an email and sms notification to the user.

The default notification also has a content() and emoji() method to set the notification content and icon.

Symfony provides the following recipients:

:class:`Symfony\\Component\\Notifier\\Recipient\\NoRecipient`
This is the default and is useful when there is no need to have information about the receiver. For example, the browser channel uses the current requests' :ref:`session flashbag <flash-messages>`;
:class:`Symfony\\Component\\Notifier\\Recipient\\Recipient`
This can contain both the email address and the phone number of the user. This recipient can be used for all channels (depending on whether they are actually set).

Configuring Channel Policies

Instead of specifying the target channels on creation, Symfony also allows you to use notification importance levels. Update the configuration to specify what channels should be used for specific levels (using channel_policy):

.. configuration-block::

    .. code-block:: yaml

        # config/packages/notifier.yaml
        framework:
            notifier:
                # ...
                channel_policy:
                    # Use SMS, Slack and email for urgent notifications
                    urgent: ['sms', 'chat/slack', 'email']

                    # Use Slack for highly important notifications
                    high: ['chat/slack']

                    # Use browser for medium and low notifications
                    medium: ['browser']
                    low: ['browser']

    .. code-block:: xml

        <!-- config/packages/notifier.xml -->
        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xmlns:framework="http://symfony.com/schema/dic/symfony"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd
                http://symfony.com/schema/dic/symfony
                https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">

            <framework:config>
                <framework:notifier>
                    <!-- ... -->

                    <framework:channel-policy>
                        <!-- Use SMS, Slack and Email for urgent notifications -->
                        <framework:urgent>sms</framework:urgent>
                        <framework:urgent>chat/slack</framework:urgent>
                        <framework:urgent>email</framework:urgent>

                        <!-- Use Slack for highly important notifications -->
                        <framework:high>chat/slack</framework:high>

                        <!-- Use browser for medium and low notifications -->
                        <framework:medium>browser</framework:medium>
                        <framework:low>browser</framework:low>
                    </framework:channel-policy>
                </framework:notifier>
            </framework:config>
        </container>

    .. code-block:: php

        // config/packages/notifier.php
        use Symfony\Config\FrameworkConfig;

        return static function (FrameworkConfig $framework): void {
            // ...
            $framework->notifier()
                // Use SMS, Slack and email for urgent notifications
                ->channelPolicy('urgent', ['sms', 'chat/slack', 'email'])
                // Use Slack for highly important notifications
                ->channelPolicy('high', ['chat/slack'])
                // Use browser for medium and low notifications
                ->channelPolicy('medium', ['browser'])
                ->channelPolicy('low', ['browser'])
            ;
        };

Now, whenever the notification's importance is set to "high", it will be sent using the Slack transport:

// ...
class InvoiceController extends AbstractController
{
    #[Route('/invoice/create')]
    public function invoice(NotifierInterface $notifier): Response
    {
        // ...

        $notification = (new Notification('New Invoice'))
            ->content('You got a new invoice for 15 EUR.')
            ->importance(Notification::IMPORTANCE_HIGH);

        $notifier->send($notification, new Recipient('[email protected]'));

        // ...
    }
}

Customize Notifications

You can extend the Notification or Recipient base classes to customize their behavior. For instance, you can overwrite the getChannels() method to only return sms if the invoice price is very high and the recipient has a phone number:

namespace App\Notifier;

use Symfony\Component\Notifier\Notification\Notification;
use Symfony\Component\Notifier\Recipient\RecipientInterface;
use Symfony\Component\Notifier\Recipient\SmsRecipientInterface;

class InvoiceNotification extends Notification
{
    public function __construct(
        private int $price,
    ) {
    }

    public function getChannels(RecipientInterface $recipient): array
    {
        if (
            $this->price > 10000
            && $recipient instanceof SmsRecipientInterface
        ) {
            return ['sms'];
        }

        return ['email'];
    }
}

Customize Notification Messages

Each channel has its own notification interface that you can implement to customize the notification message. For instance, if you want to modify the message based on the chat service, implement :class:`Symfony\\Component\\Notifier\\Notification\\ChatNotificationInterface` and its asChatMessage() method:

// src/Notifier/InvoiceNotification.php
namespace App\Notifier;

use Symfony\Component\Notifier\Message\ChatMessage;
use Symfony\Component\Notifier\Notification\ChatNotificationInterface;
use Symfony\Component\Notifier\Notification\Notification;
use Symfony\Component\Notifier\Recipient\RecipientInterface;

class InvoiceNotification extends Notification implements ChatNotificationInterface
{
    public function __construct(
        private int $price,
    ) {
    }

    public function asChatMessage(RecipientInterface $recipient, string $transport = null): ?ChatMessage
    {
        // Add a custom subject and emoji if the message is sent to Slack
        if ('slack' === $transport) {
            $this->subject('You\'re invoiced '.strval($this->price).' EUR.');
            $this->emoji("money");
            return ChatMessage::fromNotification($this);
        }

        // If you return null, the Notifier will create the ChatMessage
        // based on this notification as it would without this method.
        return null;
    }
}

The :class:`Symfony\\Component\\Notifier\\Notification\\SmsNotificationInterface`, :class:`Symfony\\Component\\Notifier\\Notification\\EmailNotificationInterface` and :class:`Symfony\\Component\\Notifier\\Notification\\PushNotificationInterface` also exists to modify messages sent to those channels.

Customize Browser Notifications (Flash Messages)

The default behavior for browser channel notifications is to add a :ref:`flash message <flash-messages>` with notification as its key.

However, you might prefer to map the importance level of the notification to the type of flash message, so you can tweak their style.

you can do that by overriding the default notifier.flash_message_importance_mapper service with your own implementation of :class:`Symfony\\Component\\Notifier\\FlashMessage\\FlashMessageImportanceMapperInterface` where you can provide your own "importance" to "alert level" mapping.

Symfony currently provides an implementation for the Bootstrap CSS framework's typical alert levels, which you can implement immediately using:

.. configuration-block::

    .. code-block:: yaml

        # config/services.yaml
        services:
            notifier.flash_message_importance_mapper:
                class: Symfony\Component\Notifier\FlashMessage\BootstrapFlashMessageImportanceMapper

    .. code-block:: xml

        <?xml version="1.0" encoding="UTF-8" ?>
        <container xmlns="http://symfony.com/schema/dic/services"
            xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
            xsi:schemaLocation="http://symfony.com/schema/dic/services
                https://symfony.com/schema/dic/services/services-1.0.xsd">

            <services>
                <service id="notifier.flash_message_importance_mapper" class="Symfony\Component\Notifier\FlashMessage\BootstrapFlashMessageImportanceMapper"/>
            </services>
        </container>

    .. code-block:: php

        // config/services.php
        namespace Symfony\Component\DependencyInjection\Loader\Configurator;

        use Symfony\Component\Notifier\FlashMessage\BootstrapFlashMessageImportanceMapper;

        return function(ContainerConfigurator $containerConfigurator) {
            $containerConfigurator->services()
                ->set('notifier.flash_message_importance_mapper', BootstrapFlashMessageImportanceMapper::class)
            ;
        };

Testing Notifier

Symfony provides a :class:`Symfony\\Bundle\\FrameworkBundle\\Test\\NotificationAssertionsTrait` which provide useful methods for testing your Notifier implementation. You can benefit from this class by using it directly or extending the :class:`Symfony\\Bundle\\FrameworkBundle\\Test\\KernelTestCase`.

See :ref:`testing documentation <notifier-assertions>` for the list of available assertions.

Disabling Delivery

While developing (or testing), you may want to disable delivery of notifications entirely. You can do this by forcing Notifier to use the NullTransport for all configured texter and chatter transports only in the dev (and/or test) environment:

# config/packages/dev/notifier.yaml
framework:
    notifier:
        texter_transports:
            twilio: 'null://null'
        chatter_transports:
            slack: 'null://null'

Using Events

The :class:`Symfony\\Component\\Notifier\\Transport` class of the Notifier component allows you to optionally hook into the lifecycle via events.

The MessageEvent::class Event

Typical Purposes: Doing something before the message is sent (like logging which message is going to be sent, or displaying something about the event to be executed.

Just before sending the message, the event class MessageEvent is dispatched. Listeners receive a :class:`Symfony\\Component\\Notifier\\Event\\MessageEvent` event:

use Symfony\Component\Notifier\Event\MessageEvent;

$dispatcher->addListener(MessageEvent::class, function (MessageEvent $event): void {
    // gets the message instance
    $message = $event->getMessage();

    // log something
    $this->logger(sprintf('Message with subject: %s will be send to %s', $message->getSubject(), $message->getRecipientId()));
});

The FailedMessageEvent Event

Typical Purposes: Doing something before the exception is thrown (Retry to send the message or log additional information).

Whenever an exception is thrown while sending the message, the event class FailedMessageEvent is dispatched. A listener can do anything useful before the exception is thrown.

Listeners receive a :class:`Symfony\\Component\\Notifier\\Event\\FailedMessageEvent` event:

use Symfony\Component\Notifier\Event\FailedMessageEvent;

$dispatcher->addListener(FailedMessageEvent::class, function (FailedMessageEvent $event): void {
    // gets the message instance
    $message = $event->getMessage();

    // gets the error instance
    $error = $event->getError();

    // log something
    $this->logger(sprintf('The message with subject: %s has not been sent successfully. The error is: %s', $message->getSubject(), $error->getMessage()));
});

The SentMessageEvent Event

Typical Purposes: To perform some action when the message is successfully sent (like retrieve the id returned when the message is sent).

After the message has been successfully sent, the event class SentMessageEvent is dispatched. Listeners receive a :class:`Symfony\\Component\\Notifier\\Event\\SentMessageEvent` event:

use Symfony\Component\Notifier\Event\SentMessageEvent;

$dispatcher->addListener(SentMessageEvent::class, function (SentMessageEvent $event): void {
    // gets the message instance
    $message = $event->getOriginalMessage();

    // log something
    $this->logger(sprintf('The message has been successfully sent and has id: %s', $message->getMessageId()));
});